Perceptual threshold to cutaneous electrical stimulation in patients with spinal cord injury

Abstract

Study design: Prospective experimental. Objectives: The aim of this study was to develop a quantitative sensory test (QST) that could be used for assessing the level and the density (degree of impairment) of spinal cord injury (SCI) and for monitoring neurological changes in patients with SCI. Setting: National Spinal Injuries Centre, Stoke Mandeville Hospital, Buckinghamshire Hospitals NHS Trust, UK. Methods: Perceptual threshold to 3 Hz cutaneous electrical stimulation was measured in 30 control subjects and in 45 patients with SCI at American Spinal Injuries Association (ASIA) sensory key points for selected dermatomes between C3 and S2 bilaterally. Electrical perceptual threshold (EPT) was recorded as the lowest ascending stimulus intensity out of three tests at which the subject reported sensation. The level of SCI according to EPT results was established for right and left sides as the most caudal spinal segment at which patient's EPT was within the control range (mean72 standard deviation (SD)). The level of SCI, according to EPT, was then compared with clinical sensory level derived according to ASIA classification. Results: In the control group, EPT depended on the dermatome tested and was lowest for T1 (1.0170.23 mA, mean7SD) and highest for L5 (3.3271.14 mA). There was strong correlation between corresponding right and left dermatomes and between repeated assessments. In the SCI group, the level of lesion according to EPT and clinical testing was the same in 43 of the 90 tests (48%). In 37 cases (41%), the EPT level was higher than the clinical level, and in 10 cases (11%), it was lower. Below the level of lesion in incomplete SCI and in the zone of partial preservation in complete SCI, the EPT values in most dermatomes were raised compared with the control group. Conclusions: EPT is a simple, reproducible QST that can assess both the level and the density of SCI. It seems to add sensitivity and resolution to the standard clinical testing and could be a useful adjunct in longitudinal monitoring of patients with SCI for research purposes during natural recovery and therapeutic interventions.

Sensitivity to change of the cutaneous electrical perceptual threshold test in longitudinal monitoring of spinal cord injury

“…Standardized stimulation sites were used, as in the two previous studies. 2,3 Additionally, a computer-controlled algorithm that further minimizes the rater variability was employed, as in the reliability study. 3 The EPT test was already shown to have good intra-and inter-rater reliability in control subjects 1,10 and in patients with SCI.…”

“…[1][2][3] The need for improved and more sensitive outcome measures for SCI clinical trials has been emphasized repeatedly. [4][5][6][7] This is especially true of therapeutic clinical trials that, for safety reasons, may target patients with thoracic lesion, where current clinical assessment tools are not sensitive enough to detect minor neurological changes.…”

Light touch and pin prick disparity in the International Standard for Neurological Classification of Spinal Cord Injury (ISNCSCI)

“…2 LT scores for individual dermatomes could be matched with electrical perceptual thresholds 17 or dermatomal sensory evoked potentials, 18 and PP with temperature thresholds 19 or contact heat evoked potentials. 20 In the interim, the results are of significance regarding the importance of the PP test as a prognostic indicator for recovery.…”

The Sir Ludwig Guttmann Lecture 2012: the contribution of Stoke Mandeville Hospital to spinal cord injuries

“…[57][58][59][60] AGEING AND SURVIVAL Together with the Northwest Regional Spinal Injuries Centre, Southport, UK, and in collaboration with Craig Hospital, Englewood, CO, USA, we have undertaken a longitudinal study on Ageing with SCI in order to provide information on health, functional ability and psychosocial wellbeing in persons with long-term spinal cord injury. 61 In 1990, when the study started, all participants had been injured more than 20 years previously.…”